Arrangement of electronic semiconductor components on a carrier system for treating said semiconductor components with a liquid medium

ABSTRACT

The invention relates to an arrangement of electronic semiconductor components on a carrier system for treating the semiconductor components with a liquid medium. A semiconductor component is detachably mounted on the carrier system with the active side thereof in such a way that the arrangement comprises a gap at least in the edge region and partially between the semiconductor components and the carrier system. The aim of the invention is to provide a detachable arrangement of electronic semiconductor components on a mechanically stable carrier system for safely handling the semiconductor components during the production process, wherein the capillarity of the gap between the semiconductor components and the carrier system is reduced in a controlled manner, thus preventing the damaging effect of a liquid medium seeping into the gap. To this end, the surface of the carrier system is shaped in such a way that the gap is widened along the entire edge region thereof.

This application is a continuation of co-pending InternationalApplication No. PCT/DE2004/002164, filed Sep. 29, 2004, which designatedthe United States and was not published in English, and which is basedon German Application No. 203 18 462.9, filed Nov. 26, 2003, both ofwhich applications are incorporated herein by reference.

TECHNICAL FIELD

The invention relates to an arrangement of electronic semiconductorcomponents on a carrier system for treating the semiconductor componentswith a liquid medium.

BACKGROUND

The arrangement of an electronic semiconductor component with the activeside downward (face down) on a carrier system, so that there is at leastin certain portions an edge between the semiconductor component and thecarrier system in a way corresponding to the topography of thesemiconductor component, is very frequently encountered in semiconductortechnology. A gap may be required for technical process-related reasonsand the medium flowing around the gap is chosen such that the gap isoptimally filled under the influence of its capillary action, such as,for example, for the underfilling of the electronic semiconductorcomponent in flip-chip technology.

Alternatively, the capillary action of the gap may lead to undesiredflowing of the liquid medium under the semiconductor component. In anyevent, it is known that the capillary action depends on the width of thegap and the surface tension of the liquid medium as its material-typicalproperty.

The flowing of a medium, in particular an etching medium, under thesemiconductor component is to be prevented, since in the case offace-down mounting of the semiconductor component it can lead toundefined etching of its active side and, as a result, damage or evendestruction of the electronic component.

This aspect is becoming increasingly significant in thin-wafertechnology, since ever larger wafers are being produced at ever lowercost and in an ever thinner form, and ever greater requirements have tobe met with respect to safe handling of the thin wafers as products.This requires the development of carrier technologies that allow safehandling of the thin wafers during production.

The handling of the electronic semiconductor components, in this case inthe wafer array, on a carrier system leads to the active side of theelectronic semiconductor components being influenced in the waydescribed, in particular during wafer thinning by grinding in thepresence of an abrasive liquid medium and by wet-chemical back etchingof the wafer, the components being located within the gap in theface-down arrangement of the wafers on the carrier system and likewiseexposed to the aggressive media as a result of the capillary action ofthe gap.

In the past, the damage to the semiconductor components has beenminimized by frequent changing of the carrier system or by the thinwafers being handled for a short time, which however leads to a specialeffort being required and to increased costs, also on account of thesusceptibility of the thin wafers to fracture.

A further possibility for protecting the active side of wafers from theaggressive media is at present to attach an adhesive film to this side.However, the film material drastically limits the temperature range thatis available for the further process, generally to below 100° C. Afurther major disadvantage of this method is that the requirement toremove the film again requires the thin wafer to be of a certainthickness, which must be great enough to withstand the mechanical forcesduring the detachment of the film. This condition currently restrictsthe thickness of the thin wafers to about 100 μm. However, futuretechnologies require far smaller wafer and component thicknesses.

SUMMARY OF THE INVENTION

The invention is consequently based on the object of providing adetachable arrangement of electronic semiconductor components on amechanically stable carrier system for safely handling the semiconductorcomponents as products in the production process, in which the capillaryaction of the gap between the semiconductor components and the carriersystem is reduced in a controlled manner and consequently the damaginginfluence of a liquid medium seeping into the gap is prevented.

The object is achieved according to the invention by the surface of thecarrier system having a profiling, which widens the gap in its entireedge region. As known, the depth of penetration into a gap acting as acapillary depends not only on the wetting properties of the materialsthat are present in the gap, that is to say the electronic semiconductorcomponents and the carrier system, but also both on the properties ofthe liquid medium that is present, in particular the surface tension,and on the width of the gap. While the depth of penetration behaves inproportion to the surface tension of the medium, there is an inverselyproportional relationship between the depth of penetration and the gapwidth.

Since it is only possible in individual cases for the materials of theelectronic semiconductor components and the carrier system to beinfluenced in such a way that the depth of penetration of the mediuminto the gap is reduced and also the liquid medium is dependent on theprocess parameters, the relationship between the depth of penetrationand the gap width is exploited and the penetration of the flowablemedium that is present at the gap is prevented, or at least controlled,by the locally limited widening according to the invention of the gapbetween the electronic semiconductor component and the carrier system inits edge region.

This arrangement consequently makes it possible to use a carrier mediumthat is mechanically and thermally stable and does not have to adaptitself to the topography of the semiconductor components in order toavoid or at least minimize a gap. Carrier systems of this type ensureboth safe handling in the production process on account of their ownstability, required for this, and the mechanical attachment on thecarrier system and the subsequent detachment of the semiconductorcomponents. The mechanical attachment may be performed for example bymethods that are known and suitable, such as spot adhesion or spot laserwelding.

The form of the widening of the gap depends substantially on thetopography of the active side of the semiconductor components that isfacing the gap. If, for example, it is planar or at least virtuallyplanar, the widening is performed exclusively by the profiling of thecarrier system. If, on the other hand, there is a tapering on the gapside in the edge region of the semiconductor components, this mayalready be considered as partial gap widening and be included in thedesired form of the edge of the gap.

Depressions in the surface of the electronic semiconductor componentsthat is facing the gap, extending from the edge of the gap into the gap,are also to be taken into account when forming the widening of the gapnear the edge. In the case of highly structured surfaces, it may well bepossible that the flowing of the liquid medium into the gap is notcompletely prevented but merely reduced or made more controllable withregard to the depth or with regard to certain portions of the gap.

One particular refinement of the invention provides that the widening ofthe gap between the electronic semiconductor component and the carriersystem is created by a channel that extends substantially parallel tothe edge of the gap. Such a channel will be suitable for use inparticular in the case of semiconductor component surfaces with littlestructuring and can be introduced for example by simple mechanical orwet-chemical processes into variously formed carrier systems, includingat certain portions of the surface, so that the form of the carriersystem does not have to correspond to that of the semiconductorcomponents.

It is consequently also possible to provide the carrier system with anumber of such channels that correspond in form and size to certain,standardized electronic semiconductor components, so that a carriersystem can be used more flexibly.

In a favorable embodiment of the invention, on the other hand, the formand size of the carrier system corresponds substantially to the form andsize of the electronic semiconductor component and the widening of thegap between the electronic semiconductor component and the carriersystem is created by a phase on the edge of the carrier system that isfacing the electronic semiconductor component. This embodiment has theeffect of preventing a certain, not inconsiderable amount of theaggressive, liquid medium from remaining on a surface in front of thegap and of preventing special circumstances from being unwantedlyconducive to the medium subsequently flowing into the gap.

If, in a way corresponding to a refinement according to the invention,the electronic semiconductor components are in the wafer array, thecarrier system can be adapted particularly favorably with regard to theform and be profiled in the edge region of the gap on account of thewafer form of the electronic semiconductor components. A silicon waferthat has not been thinned can often be used as the carrier system. Inthis case, the phase at the edge of the carrier wafer serving as acarrier system or the channel on its surface can be introduced by thetried-and-tested, low-cost processes and a carrier system which itselfis planar to a high degree is obtained.

For this reason, this embodiment is used in the case of the waferthinning described, where the planar underlying surface is important onaccount of the low final thicknesses of the wafer to be worked. If thewafer thinning is performed for example by the known spin etching, thecarrier system is a rotationally symmetrical, rotatably mounted plate.In this case, the liquid medium is an etching medium and is applied to arotating wafer in the region of the axis of rotation, distributes itselfevenly over the back of the wafer with the aid of the centrifugal forcesand in this way leads to the desired uniform deposition of material.

The etching medium, transported to the edge of the wafer by thecentrifugal forces, flows around its edge and is prevented from flowingunder the wafer and from damaging undercutting of the wafer because ofthe widening according to the invention of the gap between the wafer tobe worked and the carrier system.

These special embodiments of the invention are also used in mechanicalwafer thinning. Here, however, the liquid medium is the abrasive fluid,which contains abrasive particles and material particles and isconsequently likewise to be prevented from flowing between the wafer andthe carrier system as a result of the capillary action of the gap andcausing damage there to the wafer.

In a particularly favorable refinement of the invention, it is providedthat the width of the widening of the gap is dimensioned on the basisthat the depth of penetration into the gap for a defined liquid mediumand for defined materials of the electronic semiconductor components andof the carrier system following the widening is at least virtually zero.As described at the beginning, the characteristic variables of thesematerials likewise have an influence on the depth of penetration of theliquid medium into the gap.

Not only can the gap-forming materials of the electronic semiconductorcomponents and of the carrier system only be made hydrophobic, andconsequently suppress the capillary action, in individual cases, butalso the liquid medium itself is generally determined by therequirements of the process. However, with knowledge of the propertiesof these materials that determine the capillary action, the wettingbehavior and the surface tension, and knowledge of further influencingvariables, the depth of penetration of the liquid medium into the gapcan be set very well by means of the width and the depth of the wideningof the gap. Such further influencing factors would be, for example, thecentrifugal force in the spin-etching process, which counteracts thecapillary force and can be easily regulated. Consequently, the action ofthe liquid medium that is present can be controlled in a specific mannerfor defined applications.

DESCRIPTION OF THE DRAWINGS

The invention is to be explained in more detail below on the basis of anexemplary embodiment. In the associated drawing:

FIG. 1 shows a schematic partial sectional representation of thearrangement according to the invention on a chuck with gap widening inthe form of a channel; and

FIG. 2 shows a schematic partial sectional representation of thearrangement according to the invention with gap widening by a phase.

The following list of reference symbols can be used in conjunction withthe figures:

1 semiconductor component 2 wafer 3 active side 4 carrier system 5 ballsof adhesive 6 channel 7 gap 8 vacuum chuck 9 axis of rotation 10 etchingmedium 11 back 12 phase

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the arrangement according to the invention of electronicsemiconductor components 1 on a carrier system 4, as schematicallyrepresented in FIG. 1, the semiconductor components 1 in the wafer arrayare mounted with the active side 3, having a structure, downward (facedown) on a round carrier system 4 by spot adhesion, so that balls ofadhesive 5 detachably establish the connection between the semiconductorcomponent 1, in this exemplary embodiment the wafer 2, and the carriersystem 3 only at some locations.

The diameter of the carrier system 4 is greater than the diameter of thewafer 2. On the diameter that corresponds approximately to that of thewafer 2 the carrier system 4 has a channel 6 with a semicircular crosssection, the depth of which in the exemplary embodiment representedcorresponds approximately to the height of the gap 7 between the wafer 2and the carrier system 4, so that the gap 7 is increased in the regionof the channel 6 to twice the width.

The carrier system 4 is in turn fixed by means of a vacuum on a vacuumchuck 8. In a way similar to the carrier system 4 and the wafer 2, thevacuum chuck 8 has a circular form. All three component parts of thisarrangement are arranged rotatably on an axis of rotation 9, so that theliquid etching medium 10 applied in the region of the axis of rotation 9during the rotation is present in a virtually even distribution on theback 11 of the wafer 2 after a certain time.

The etching medium 10 coming out over the edge of the wafer 2 flowsaround the edge and fills the edge region of the gap 7 between the wafer2 and the carrier system 4, including the channel 6 formed there, andonly a very small amount enters the gap 7 via the channel 6.

FIG. 2 represents another embodiment of the profiling of the carriersystem 4, the carrier system 4 being of virtually the same size as theelectronic semiconductor components 1. According to the invention, insuch a case it is possible that the carrier system 4 has on the edgethat is facing the semiconductor components 1 a phase 12, which in theembodiment represented has virtually the cross section of a quartercircle and reduces the thickness of the carrier system 4 at its outeredge to approximately half.

1. An arrangement of a semiconductor component on a carrier system fortreating the semiconductor component with a liquid medium, wherein thesemiconductor component is mounted with an active side of thesemiconductor component facing the carrier system using adhesive ballsin such a way that the arrangement comprises a gap between thesemiconductor component and the carrier system; and an annular channeldisposed on the carrier system for collecting an etching medium, whereinthe annular channel is disposed below an outer peripheral edge of asubstrate; wherein the gap is configured to be wider in an edge regionto prevent seeping of the liquid medium in to the gap, and wherein thecarrier system comprises no gas outlets for preventing the seeping ofthe liquid medium into the gap.
 2. The arrangement as claimed in claim1, wherein the gap in the edge region between the semiconductorcomponent and the carrier system is wider due to a channel that extendssubstantially parallel to the edge region of the gap.
 3. The arrangementas claimed in claim 1, wherein the carrier system has a form and sizethat corresponds substantially to a form and size of the semiconductorcomponent and in that the gap in the edge region between thesemiconductor component and the carrier system is wider due to a phaseon the edge region of the carrier system that is facing thesemiconductor component.
 4. The arrangement as claimed in claim 1,wherein the liquid medium is an etching medium.
 5. The arrangement asclaimed in claim 1, wherein the gap at the edge region has a width thatis dimensioned based on a depth of penetration into the gap for theliquid medium and for defined materials of the semiconductor componentand of the carrier system.
 6. The arrangement of claim 1, wherein thesemiconductor component is detachably mounted to the carrier system. 7.An arrangement of a semiconductor component and a carrier system, thearrangement comprising: a carrier including an outer peripheral edge; asubstrate having an outer peripheral edge, the substrate mounted on thecarrier such that a gap of a small distance exists between a mainsurface of the carrier and a main surface of the substrate, wherein thesubstrate is attached to the carrier using ball shaped adhesive; and anannular channel disposed on the carrier for collecting an etchingmedium, wherein the annular channel is disposed below the outerperipheral edge of the substrate, wherein at the outer peripheral edge,the substrate is spaced from the carrier by a distance greater than thesaid small distance along the main surface of the substrate to preventseeping of the etching medium in to the gap, and wherein the carriercomprises no gas outlets for preventing the seeping of the etchingmedium into the gap.
 8. The arrangement of claim 7, wherein the carrierincludes a channel disposed therein, the channel having a shapecorresponding to the outer peripheral edge of the substrate such thatthe outer peripheral edge of the substrate is aligned with the channel.9. The arrangement of claim 8, wherein the channel has a semicircularcross-section.
 10. The arrangement of claim 7, wherein the substratecomprises a semiconductor wafer.
 11. The arrangement of claim 10,wherein the main surface of the substrate comprises active circuitry.12. The arrangement of claim 7, wherein the outer peripheral edge of thesubstrate is substantially aligned with the outer peripheral edge of thecarrier.
 13. The arrangement of claim 7, wherein the substrate is spacedfrom the carrier by at least twice a minimum distance along the entireouter peripheral edge of the substrate.
 14. An arrangement of asemiconductor component on a carrier system, the arrangement comprising:a substrate comprising an outer peripheral edge; a carrier including anouter peripheral edge mounted on a vacuum chuck; a gap disposed betweenthe substrate and the carrier, wherein a gap distance between the mainsurface of the carrier and a main surface of the substrate is small;adhesive balls for supporting the gap; and an annular channel disposedon the carrier for collecting an etching medium, wherein the annularchannel is disposed below the outer peripheral edge of the substrate,wherein in an area above the annular channel, the substrate is spacedfrom the carrier by a gap distance greater than the said small gapdistance along the main part of the carrier to prevent seeping of theetching medium into the gap, and wherein the carrier comprises no gasoutlets for preventing the seeping of the etching medium into the gap.15. The arrangement of claim 14, wherein the substrate and the carrierare about the same size.
 16. The arrangement of claim 15, wherein theannular channel is disposed on the outer peripheral edge of the carrier.17. The arrangement of claim 16, wherein the annular channel comprises aquarter circle, wherein the quarter circle reduces a thickness of thecarrier system at an outer edge to about a thickness of the carriersystem in an inner region.
 18. The arrangement of claim 14, wherein thegap impedes a flow of the etching medium onto the main surface of thesubstrate.
 19. The arrangement as claimed in claim 14, wherein thesemiconductor component comprises a semiconductor wafer.
 20. Thearrangement as claimed in claim 19, wherein the carrier comprises arotationally symmetrical, rotatably mounted plate.